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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:53 |
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Conference: Bucharest University Faculty of Physics 2016 Meeting
Section: Solid State Physics and Materials Science
Title:
Estimate of the lifetime of special electrical equipment
Authors:
Catalin RUSU-ZAGĂR(1), Gilda RUSU-ZAGĂR(2),
Affiliation:
1) University Politehnica , Bucharest
2) INCDPM Alexandru Darabont , Bucharest, Romania
E-mail
gildarusuzagar@yahoo.com; catalinrusuzagar@gmail.com
Keywords:
safety, lifetime, special electrical equipment
Abstract:
In general, foar all the electric equipment (generators, transformers, motors, switches) it is estimated - through accelerated testing labs-their lifetime duration. Usually, values of the equipment’s lifetime coincide with the life duration of their insulation systems, determined by constant stress tests (Thermal, electrical, mechanical) or, less commonly, variable. Requests insulation equipment in operation may vary over time and take, often, higher than nominal values. This leads to greater consumption of lifetimes and involves, to avoid damage, premature removal from service of the equipment. In the case of equipment operating under special conditions(aviation, mining, metallurgy etc.) decommissioning of these can cause considerable economic loss. Because of this, it must estimate the useful lives of the equipment in conditions as close to those of exploitation. On the other hand, equipment can go out prematurely from function due to the full consumption of lifetime of power conductors, less analyzed phenomenon in specialized literature. In this paper is presented a method for estimating rapid lifetimes of insulation electric motors used to drive the propellers helicopters and their power cables. The used method is based on the rapid determination of the activation energy through a thermal analysis DSC(differentia scaning calorimetry) and performing in parallel of a thermal accelerated aging at the highest temperature allowed by isolation . The experiments were performed on an insulating epoxy resins for motor (thermal aged at 260 oC) and on one silicone rubber for power cable(thermal aged at 180 oC). It is found that the time required for this experiments in this method is about 15 times lower than in case of using the classical method based on tests at three temperatures. Also, it has been found that, for a given temperature, thermal insulation lifetime of the cable is greater than that of the motor insulation. At the end of the paper it is showed that for a more accurate appraisal the duration of the two isolation in case of aircrafts equipements it have to be effected experiments also at thermal and mechanical requests.
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